Column 2. This is the first column in the markup. This is the page's content.The "contentarea" wrapper round the three columns is floated left like the three columns, to force it to enclose the three columns. Because of this, no matter which of the three columns is longest, the footer sits below it....
Column 1. This is the second column in the markup. This is the left navigation. The "contentarea" wrapper round the three columns is floated left like the three columns, to force it to enclose the three columns. Because of this, no matter which of the three columns is longest, the footer sits below it.
Column 3. This is the third column in the markup.